Hi, I have been using this addon for some time and am happy with it.
I have zencart 155f, standard green template and PHP 5.6

When I select a category then the sorter enter field shows up and I can sort fine.

But if I select a set of products using the built in zen cart search option, like, for example, "coat" then the relevant 46 products and the sorter enter field show up fine.
But when I try to sort I get a PHP error
Code:
[07-Aug-2018 17:00:38 Europe/Zurich] PHP Fatal error:  1064:You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'order by p.products_sort_order, pd.products_name limit 20' at line 1 :: SELECT DISTINCT p.products_image, p.products_quantity ,  p.products_sort_order, m.manufacturers_id, p.products_id, pd.products_name, p.products_price, p.products_tax_class_id, p.products_price_sorter, p.products_qty_box_status, p.master_categories_id FROM (products p              LEFT JOIN manufacturers m              USING(manufacturers_id), products_description pd, categories c, products_to_categories p2c )              LEFT JOIN meta_tags_products_description mtpd              ON mtpd.products_id= p2c.products_id              AND mtpd.language_id = 1 WHERE (p.products_status = 1                AND p.products_id = pd.products_id                AND pd.language_id = 1                AND p.products_id = p2c.products_id                AND p2c.categories_id = c.categories_id  AND ((pd.products_name LIKE '%coat%'                                          OR p.products_model                                          LIKE '%coat%'                                          OR m.manufacturers_name                                          LIKE '%coat%' OR (mtpd.metatags_keywords                         LIKE '%coat%'                         AND mtpd.metatags_keywords !='') OR (mtpd.metatags_description                         LIKE '%coat%'                         AND mtpd.metatags_description !='') OR pd.products_description                           LIKE '%coat%') )) order by p.products_price_sorter order by p.products_sort_order, pd.products_name limit 20 ==> (as called by) /home/httpd/vhosts/simmar.ch/httpdocs/catalog/includes/modules/responsive_simmar/product_listing.php on line 117 <== in /home/httpd/vhosts/simmar.ch/httpdocs/catalog/includes/classes/db/mysql/query_factory.php on line 171
My website is https://www.simmar.ch/catalog

You may want to select "english language"